Hi there,
A detailed medical and psychiatric history is always needed for every case.In addition, there is always a need for detailed mental status examination to come for a diagnosis and its management accordingly.
Coming to your problems,
Drugs like Lithium and Oleanz can produce abdominal symptoms in addition to other side effects.
Bloating or abdominal fullness can be one of them.
Their is a need for doing blood tests like
lipid profile ,
LFT ,KFT and urine investigations for the patients who are on such drugs.A detailed medical and treatment history is also needed.
Do discuss your problems with your mental health professional. There are other drugs also available who have lesser side effects and can act like the replacements for such drugs.